Page 881 - 2018_IRC

APPENDIX E

SECTION AE402 inches (203 mm) above the adjacent finish grade. Footings
LOCATION ON PROPERTY shall have a minimum depth below finished grade of 12
AE402.1 General. Manufactured homes and accessory inches (305 mm) unless a greater depth is recommended by a
buildings shall be located on the property in accordance with foundation investigation.
applicable codes and ordinances of this jurisdiction. Piers and bearing walls shall be supported on masonry or
concrete foundations or piles, or other approved foundation
systems that shall be of sufficient capacity to support all
SECTION AE501 loads.
DESIGN
AE502.4 Foundation design. Where a design is provided,
AE501.1 General. A manufactured home shall be installed the foundation system shall be designed in accordance with
on a foundation system designed and constructed to sustain the applicable structural provisions of this code and shall be
within the stress limitations specified in this code and all designed to minimize differential settlement. Where a design
loads specified in this code. is not provided, the minimum foundation requirements shall
Exception: Where specifically authorized by the building be as set forth in this code.
official, foundation and anchorage systems that are con- AE502.5 Drainage. Provisions shall be made for the control
structed in accordance with the methods specified in Sec- and drainage of surface water away from the manufactured
tion AE600 of these provisions, or in the HUD, Permanent home.
Foundations for Manufactured Housing, 1984 Edition,
Draft, shall be deemed to meet the requirements of this AE502.6 Under-floor clearances—ventilation and access.
appendix. A minimum clearance of 12 inches (305 mm) shall be main-
tained beneath the lowest member of the floor support fram-
AE501.2 Manufacturer’s installation instructions. The ing system. Clearances from the bottom of wood floor joists
installation instructions as provided by the manufacturer of or perimeter joists shall be as specified in this code.
the manufactured home shall be used to determine permissi-
ble points of support for vertical loads and points of attach- Under-floor spaces shall be ventilated with openings as
ment for anchorage systems used to resist horizontal and specified in this code. If combustion air for one or more heat-
uplift forces. producing appliance is taken from within the under-floor
spaces, ventilation shall be adequate for proper appliance
AE501.3 Rationality. Any system or method of construction operation.
to be used shall submit to a rational analysis in accordance
with well-established principles of mechanics. Under-floor access openings shall be provided. Such
openings shall be not less than 18 inches (457 mm) in any
dimension and not less than 3 square feet (0.279 m ) in area,
2
SECTION AE502 and shall be located so that any water supply and sewer drain
FOUNDATION SYSTEMS connections located under the manufactured home are acces-
sible.
AE502.1 General. Foundation systems designed and con-
structed in accordance with this section shall be considered a
permanent installation. SECTION AE503
AE502.2 Soil classification. The classification of the soil at SKIRTING AND PERIMETER ENCLOSURES
each manufactured home site shall be determined where AE503.1 Skirting and permanent perimeter enclosures.
required by the building official. The building official has the Skirting and permanent perimeter enclosures shall be
authority to require that the determination be made by an installed only where specifically required by other laws or
engineer or architect licensed by the state to conduct soil ordinances. Skirting shall be of material suitable for exterior
investigations. exposure and contact with the ground. Permanent perimeter
The classification shall be based on observation and any enclosures shall be constructed of materials as required by
necessary tests of the materials disclosed by borings or exca- this code for regular foundation construction.
vations made in appropriate locations. Additional studies may Skirting shall be installed in accordance with the skirting
be necessary to evaluate soil strength, the effect of moisture manufacturer’s installation instructions. Skirting shall be ade-
variation on soil-bearing capacity, compressibility and expan- quately secured to ensure stability, minimize vibration and
siveness.
susceptibility to wind damage, and compensate for possible
Where required by the building official, the soil classifica- frost heave.
tion design-bearing capacity and lateral pressure shall be AE503.2 Retaining walls. Where retaining walls are used as
shown on the plans. a permanent perimeter enclosure, they shall resist the lateral
AE502.3 Footings and foundations. Footings and founda- displacements of soil or other materials and shall conform to
tions, unless otherwise specifically provided, shall be con- this code as specified for foundation walls. Retaining walls
structed of materials specified by this code for the intended and foundation walls shall be constructed of approved treated
use and in all cases shall extend below the frost line. Footings wood, concrete, masonry or other approved materials or com-
of concrete and masonry shall be of solid material. Founda- bination of materials as for foundations as specified in this
tions supporting untreated wood shall extend not less than 8 code. Siding materials shall extend below the top of the exte-

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